Lewisville Aquatic Ecosystem Research Facility

The U.S. Army Engineer Research and Development Center operates the Lewisville Aquatic Ecosystem Research Facility (LAERF) in Lewisville, TX. An experimental pond facility developed by the Corps of Engineers' (CE) Aquatic Plant Control Research Program (APCRP), LAERF supports studies on biology, ecology, and management of aquatic plants. LAERF provides an intermediate-scale research environment to bridge the gap between small-scale laboratory studies and large-scale field tests. In addition to 53 earthen and 21 lined ponds, LAERF utilizes 18 flowing water raceways, 3 large outdoor mesocosm facilities, a research greenhouse, and several laboratories to conduct research activities.

Ponds and raceways are supplied with water from Lewisville Lake, an adjacent CE reservoir. Ponds are filled and drained independently for control of different hydrologic regimes. Many are equipped with adjustable stand-pipes to provide constant water levels. Flowing water raceways are used for small-scale studies on effects of flow and/or constituent loading on aquatic and wetland biota or ecosystem processes.

An outdoor chemical control mesocosm system consists of thirty 6,000-L capacity (2.5 m diameter by 1.5 m deep) and twenty-four 1,845-L fiberglass mesocosm tanks supplied with filtered, alum-treated lake water from a lined water supply pond. Mesocosms can be operated under static or flow-through conditions with submersed aquatic plants growing in containers of sediment. The mesocosm system is used for studying effects of aquatic herbicides on target and nontarget organisms as well as studies on aquatic plant biology and ecology.

A deep-water mesocosm system consists of eighteen 14,000-L capacity fiberglass tanks measuring 2.5 m in diameter and 3 m deep. These tanks share the water supply with the chemical control mesocosm system. Deepwater mesocosms are used for studying seasonal growth and development of problem aquatic plants under low light conditions.

A research greenhouse contains twenty 1,200-L capacity, temperature-controlled fiberglass tanks, which can be filled with filtered, alum-treated lake water from a 20,000-L storage tank. This system is utilized for conducting short-term, controlled experiments to supplement longer-term studies in ponds.

An on-site analytical laboratory is equipped for processing and analyzing water, plant, and sediment samples in support of research being conducted at LAERF or in the field. An ongoing water chemistry monitoring program provides information on experimental conditions occurring in ponds, mesocosms, and greenhouse tanks. Other onsite laboratory facilities are equipped for supporting studies of aquatic plants conducted in ponds, mesocosms, raceways, and greenhouses as well as studying physiological processes such as photosynthesis and respiration. Currently, 12 Hydrolab water chemistry data acquisition units are available.

APCRP research in progress includes: field testing of microbial pathogens and host-specific insects for biological control of submersed aquatic plants, studies of the efficacy of aquatic plant herbicides, studies of the effects of aquatic plants on fisheries, water quality, macroinvertebrates, and native vegetation; studies of the biology of introduced aquatic weeds such as waterhyacinth, Eurasian watermilfoil, hydrilla, and giant salvinia; and studies of methods for promoting establishment of native aquatic plant species to prevent further spread of introduced weeds.

LAERF is available to support research for other agencies when projects are compatible and complementary to ongoing research programs. Ongoing efforts include: Texas Parks and Wildlife Department (TPWD) Aquatic Habitat Establishment Initiative, a cooperative program with TPWD to introduce native aquatic plants into unvegetated reservoirs; cooperative efforts with state, city, and river authorities; water chemistry of Lake Texoma in cooperation with EPA and the University of North Texas; and cooperative research with the South Florida Water Management District on the spread of torpedograss in Lake Okeechobee.

LAERF also plays an important role in activities at the Lewisville Lake Environmental Learning Area, a 2,000-acre tract of CE land that has been leased to a consortium of local universities, the Lewisville Independent School District, and the City of Lewisville for environmental preservation, education, and research. In addition, high school and university undergraduate and graduate students are employed by LAERF as support staff for research projects, and several thesis and dissertation projects have been completed onsite. Since the inception of LAERF in 1990, more than 100 students have been employed at the facility, providing them with experience for future employment after graduation and providing dollars to the local economy.